Audible alarms, buzzers, bells, chimes, and signaling devices come in a wide variety of forms to serve a wide range of applications. Some devices are produced to provide a maximum sound output, others are designed for maximum durability, some are designed to produce a tone within a particular frequency range, some are intended to withstand the rigors of a hostile environment, and some are designed to produce a muted or pleasant tone. Many other design criteria are used, and, frequently, size is an important consideration as is also economy and the type of power available for operation. The buzzer of the present invention is designed for a.c. or d.c. use and, as is understood by those famiilar with such devices, a substitution of one coil for another, and/or minor mechanical adjustments, will permit use with a.c. or d.c. potential sources with a wide range of input potential. The buzzer disclosed herein is designed for maximum economy in manufacture and is small, but not of microminiature size. While the buzzer is designed to produce a significant sound, it is not designed for a maximum ratio of sound output to power input, nor to produce a signal of any specific and controlled frequency.
Buzzers which have some construction characteristics in common with the buzzer disclosed herein are shown in U.S. Pat. No. 3,864,823 and 3,931,549, both issued to Charles Berns and assigned to the same assignee as the present invention.
In years past, devices of this general nature were fabricated using considerable hand labor. However, the cost of labor has become so significant that it is frequently economical to design devices for automated assembly, using intricate and costly assembly machines to replace human labor. The buzzer of the present invention is designed to permit automated assembly in moderate quantities.
One problem which arises, with respect to automated assemblies, is that frequently two parts must be assembled with a specific relative orientation in order to admit the placement of a third part. Frequently, the subassembly of the two parts must be moved from the station where they are assembled to a second where the third part is inserted. If there is any relative motion of the first two parts, as the subassembly is moved from the first station to the second station, the third part cannot be inserted without breakage or human intervention. The problem has been solved in the prior art by the use of special components and/or close design tolerances. However, it is evident that the use of special components and close tolerances increase cost.